Angles In Circles Tutorial for calculating angles in circles formed from radii, chords, tangents and secants.
Calculator for Constructing Regular Polygons
Draw a circle, measure the radius and this calculates the length of the polygon's sides.
Central Angle Calculator Calculates a Circle's Central Angle, Radius or Arc Length
Circle Circumference & Area Calculator
CIRCLE Calculator for Radius, Central Angle, Chord, Segment Height, Apothem, Arc Length and Chord Length. If you know two, it will calculate the other five as well as the Sector Area, Segment Area and Circle Area.
Circle Equation Tutorial
Explains equations of the type x² + y² = r²
Circle Equation Calculator
Input 3 points and it calculates a circle's center radius and equation.
Calculator and tutorial
Types of Triangles
A chart showing triangles classified by angles
(acute, right, obtuse) and by sides (equilateral, isosceles, scalene).
Also has triangle area formulas and a triangle area calculator.
A tutorial discussing the incenter, circumcenter, centroid, orthocenter and the Euler line.
Calculates if 3 sides will form a triangle or not.
Right Triangles (Pythagorean Theorem)
30 60 90 and 45 45 90 Triangle Calculator
Regular Polygon Calculator
Input the number of sides and the side length and it calculates the polygon perimeter, all angles (interior, central and exterior), the inradius, the circumradius and the total area.
Input side length and either angle and it calculates the area, both diagonals, altitude, perimeter.
Input both diagonals and it calculates the side, area, altitude, perimeter and both angles.
Quadrilateral page Descriptions and graphics discussing 6 different types of quadrilaterals.
How to Calculate Trapezoid Area
Calculator for Parallelograms Squares Rectangles Rhombuses
Quadrilateral Kite Calculator